Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » B »

BIOS - basic input output system

(bī´ōs) BIOS is an acronym for basic input/output system, the built-in software that determines what a computer can do without accessing programs from a disk. The BIOS is an important part of any computer system. On personal computers (PCs), for example, the BIOS contains all the code required to control the keyboard, display screen, disk drives, serial communications, and a number of miscellaneous functions.

The ROM BIOS Explained

The BIOS is typically placed in a ROM chip that comes with the computer (it is often called a ROM BIOS). This ensures that the BIOS will always be available and will not be damaged by disk failures. It also makes it possible for a computer to boot itself. Because RAM is faster than ROM, though, many computer manufacturers design systems so that the BIOS is copied from ROM to RAM each time the computer is booted. This is known as shadowing.

Many modern PCs have a flash BIOS, which means that the BIOS has been recorded on a flash memory chip, which can be updated if necessary.

PC BIOS Standardization

The PC BIOS is fairly standardized, so all PCs are similar at this level (although there are different BIOS versions). Additional DOS functions are usually added through software modules. This means you can upgrade to a newer version of DOS without changing the BIOS.

Newer PC BIOSes that can handle Plug-and-Play (PnP) devices are known as PnP BIOSes, or PnP-aware BIOSes. These BIOSes are always implemented with flash memory rather than ROM.







TECH RESOURCES FROM OUR PARTNERS
LATEST ARTICLES
What's Hot in Tech: AI Tops the List

Like everything in technology, AI touches on so many other trends, like self-driving cars and automation, and Big Data and the Internet of Things... Read More »

DevOp's Role in Application Security

As organizations rush to release new applications, security appears to be getting short shrift. DevSecOps is a new approach that holds promise. Read More »

Slideshow: Easy Editorial SEO Tips to Boost Traffic

This slideshow reviews five easy on-page editorial SEO tips to help drive organic search engine traffic, including the page title, heading,... Read More »

STUDY GUIDES
Java Basics, Part 1

Java is a high-level programming language. This guide describes the basics of Java, providing an overview of syntax, variables, data types and... Read More »

Java Basics, Part 2

This second Study Guide describes the basics of Java, providing an overview of operators, modifiers and control Structures. Read More »

The 7 Layers of the OSI Model

The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »